Typical ring laser gyros include a cavity disposed within a solid gyro body, the cavity forming a closed loop path. The gyro further includes a cathode and a pair of anodes, each of which is in communication with the cavity. Suitable means are provided for establishing a gas discharge between the cathode and each of the anodes so as to generate a pair of counter-rotating laser beams traveling through the cavity.
Known cathode arrangements for ring laser gyros have included a metal cathode member having a substantially semi-spherical outer surface. About the periphery of the lower edge of the cathode member, an outwardly extending metal flange is typically provided for securing the cathode member to an upper surface of the gyro body. The metal flange of the cathode member is typically secured to the quartz body of the ring laser gyro by means of an indium seal. The metal to glass seal often fails due to stresses therein caused by changes in temperature and the like. Therefore, such cathode arrangements have a very limited life. Another problem with known cathode arrangements is cathode sputtering wherein a discharge between the cathode and anodes results in ions bombarding the metal cathode member causing an ejection of atoms from the surface thereof, the sputtering typically occurring around sharp corners of the member such as near the flange. Further, because the metal cathode member is seated on the upper surface of the ring laser gyro body, the cathode arrangement has a high profile adding to the overall height of the gyro. In applications where the size of the gyro must be minimized, such known cathode arrangements are undesirable.